Comparison of 3 Phenotypic-detection Methods for Identifying Plasmid-mediated AmpC beta-lactamase-producing Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis Strains.
10.3343/kjlm.2009.29.5.448
- Author:
Wookeun LEE
1
;
Bochan JUNG
;
Seong Geun HONG
;
Wonkeun SONG
;
Seok Hoon JEONG
;
Kyungwon LEE
;
Hyo Sun KWAK
Author Information
1. Department of Laboratory Medicine, CHA University, Sungnam, Korea. hlseo@cha.ac.kr
- Publication Type:Original Article ; Comparative Study ; Research Support, Non-U.S. Gov't
- Keywords:
AmpC beta-lactamase;
Boronic acid;
Hodge test;
Tris-EDTA disk test
- MeSH:
Anti-Bacterial Agents/pharmacology;
Bacterial Proteins/*analysis;
Cefotetan/pharmacology;
Cefoxitin/pharmacology;
Disk Diffusion Antimicrobial Tests/*methods;
Escherichia coli/genetics/*isolation & purification;
Humans;
Klebsiella pneumoniae/genetics/*isolation & purification;
Phenotype;
Plasmids;
Proteus mirabilis/genetics/*isolation & purification;
Sensitivity and Specificity;
beta-Lactamases/*analysis
- From:The Korean Journal of Laboratory Medicine
2009;29(5):448-454
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: Plasmid-mediated AmpC beta-lactamases (PABLs) have been detected in the strains of Escherichia coli, Klebsiella spp., Proteus mirabilis, and Salmonella spp. PABLs may be difficult to detect and might interfere in the therapeutic and infection-control processes. Although several PABL-detection methods based on phenotypes have been reported, the Clinical and Laboratory Standards Institute currently does not recommend a routine detection method for PABLs. The aim of this study is to compare the performances of 3 phenotypic PABL detection methods. METHODS: Total 276 non-duplicated clinical isolates of E. coli (N=97), K. pneumoniae (N=136), and P. mirabilis (N=43) were collected from 14 hospitals in Korea between April and June 2007 in a non-consecutive and non-random manner. Multiplex PCR was performed to detect the PABL genes. Further, 3 phenotypic detection methods-cephamycin-Hodge test, Tris-EDTA (TE) disk test, and combination-disk test with 3-aminophenylboronic acid (BA)-were performed using cefoxitin and cefotetan disks. RESULTS: PABL genes were detected by multiplex PCR in 122/276 isolates, including 14/97 E. coli, 105/136 K. pneumoniae, and 3/43 P. mirabilis isolates. The combination-disk test with BA showed higher sensitivity (98.4%), specificity (92.2%), and efficiency (96.3%) than the cephamycin-Hodge (76.2%, 96.1%, and 88.6%, respectively) and the TE-disk (80.3%, 91.6%, and 87.9%, respectively) tests. CONCLUSIONS: The combination-disk test with BA is a simple, efficient, and interpretable test that can be applicable in clinical laboratories involved in the detection of PABLs in clinical isolates of E. coli, K. pneumoniae, and P. mirabilis.
